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package com.oracle.truffle.llvm.parser.model.symbols.instructions;

import com.oracle.truffle.llvm.parser.model.SymbolImpl;
import com.oracle.truffle.llvm.parser.model.SymbolTable;
import com.oracle.truffle.llvm.parser.model.blocks.InstructionBlock;
import com.oracle.truffle.llvm.parser.model.visitors.SymbolVisitor;
import com.oracle.truffle.llvm.runtime.types.MetaType;

public final class CatchSwitchInstruction extends ValueInstruction implements TerminatingInstruction {

    private final InstructionBlock block;
    private final InstructionBlock unwind;
    private SymbolImpl within;
    private final InstructionBlock[] cases;

    /**
     * @param block The instruction block this instruction is in
     */
    private CatchSwitchInstruction(InstructionBlock block, InstructionBlock[] cases, InstructionBlock unwind) {
        super(MetaType.TOKEN);
        assert cases.length > 0;
        this.block = block;
        this.cases = cases;
        this.unwind = unwind;
    }

    public InstructionBlock getInstructionBlock() {
        return block;
    }

    public InstructionBlock getFirstCase() {
        return cases[0];
    }

    public boolean hasUnwindBlock() {
        return unwind != null;
    }

    public InstructionBlock getUnwindBlock() {
        return unwind;
    }

    @Override
    public void replace(SymbolImpl oldValue, SymbolImpl newValue) {
        if (within == oldValue) {
            within = newValue;
        }
    }

    @Override
    public void accept(SymbolVisitor visitor) {
        visitor.visit(this);
    }

    public static CatchSwitchInstruction generate(SymbolTable table, InstructionBlock block, int withinIndex, InstructionBlock[] cases, InstructionBlock unwind) {
        CatchSwitchInstruction l = new CatchSwitchInstruction(block, cases, unwind);
        l.within = table.getForwardReferencedOrNull(withinIndex, l);
        return l;
    }

    @Override
    public int getSuccessorCount() {
        return hasUnwindBlock() ? cases.length + 1 : cases.length;
    }

    @Override
    public InstructionBlock getSuccessor(int index) {
        assert index < cases.length || (unwind != null && index == cases.length);
        return index < cases.length ? cases[index] : unwind;
    }
}
